1. Field of the Invention
The present invention pertains to an apparatus that detects its own instability and performs prescribed processing regarding said instability based on the detected shake amounts.
2. Description of the Prior Art
When taking a photograph, instability or camera shake of the camera relative to an object caused by hand shake is one obstacle to taking a proper photograph. This camera shake is known through experience to have essentially common characteristics. Therefore, by detecting this instability, its effect can be effectively eliminated.
In addition, when performing viewing through binoculars, instability of the binoculars relative to the viewing object caused by hand shake is one factor that hinders clear observation.
In recent years, a camera has been proposed that detects by means of a CCD (charge coupled device) area sensor the degree of instability of the camera relative to the object due to hand shake and that performs shake correction by driving a correction lens such that the shake will be eliminated. In other words, as the object image is repeatedly received by the area sensor, the captured image data is sent to the shake amount detector. This shake detector first extracts and specifies a base image from the object image that is first transmitted to it. Reference images that correspond to the base image are extracted from the object image data that is sequentially received and sent to the detector, such that the changes (shake) between the base image and reference images may be detected in terms of a number of CCD pixels. Next, using the shake amounts thus obtained, an estimated shake amount is calculated based on the time that will elapse between the time at which the detections were performed and the time at which the correction lens is driven. By driving the correction lens in accordance with the estimated shake amount thus obtained, the movement in the object image due to hand shake is effectively eliminated.
When preparatory photo-taking operations are performed, said shake detection and shake amount calculation operations are repeatedly performed. When the shutter release operation is then performed, during the exposure period, while shake detection and shake calculation are performed, calculation of an estimated shake amount is also carried out, data corresponding to the estimated shake amount is set in the drive unit, and the correction lens is caused to carry out the shake correction operation.
In said conventional camera, shake detection and shake amount calculation are performed both during photo-taking preparation and during exposure, without differentiating between the two, but shake correction is not actually performed during the photo-taking preparation period.
Given that the shake detection cycles are relatively short in order to perform shake correction with high accuracy while keeping up with hand shake and that the camera is driven by a battery housed in it, performing the same operations during photo-taking preparation that are performed during actual exposure leads to wasteful power consumption.
Displaying the repeatedly-obtained shake amounts on a monitor is desirable because the operator can be notified of the existence of hand shake and his attention can be called to this fact before photo-taking is performed. However, if the shake amount is displayed each time shake calculation is performed, the display will change frequently. This makes the displayed values hard to discern and existence of hand shake difficult to confirm.